The crucial point is one of corporate memory. When the people who were good on the operations were on occasion phased out in favour of people who were good at driving retail sales from Terminal space, the ability to react to any cold snap went with them. Simply put, such skills get forgotten, neglected and fall down the list of priorities.
The major airports all made a complete **** up since 2008 when snow falls, Manchester and Gatwick now get the praise over Heathrow. However the order in which they got caught with their pants down is Manchester, Gatwick, Heathrow, the same order in which the heavy snow affected their fields.
The good news is MAN and LGW are further along the learning curve than LHR. The question is, will they forget it again as the years pass and the winters get milder? Incidentally, the muppets rock.
"It's time to play the music, It's time to light the lights...." Enough I think.